1. Field of the Invention
The present invention relates to a locking device for a detachable bicycle top tube assembly and, more particularly, to a locking device for reliably locking a detachable bicycle top tube between a head top and a seat tube of a bicycle when the detachable bicycle top tube is mounted to the bicycle to be carried by, e.g., a car.
2. Description of the Related Art
It is popular to cycling in suburb and most of the users carry a bicycle by a car. Typically, a bicycle includes a top tube that can be attached to and thus carried by the car. However, some of the bicycles equipped with cushioning devices have no such top tube. FIG. 9 of the drawings illustrates a conventional detachable top tube that can be removably attached between the head tube (not shown) and the seat tube 3xe2x80x2 of a bicycle. The top tube comprises two tube sections 1xe2x80x2 and 6xe2x80x2 that are connected together by a member 7xe2x80x2 to thereby allow adjustment in an overall length of the top tube. Attached to an outer end of each top tube section 1xe2x80x2, 6xe2x80x2 is a hook-like attaching member 2xe2x80x2 that is mounted around the set tube 3xe2x80x2 or the head tube. A latch member 4xe2x80x2 is pivotally attached to the tube section 1xe2x80x2, 6xe2x80x2 by a pin 5xe2x80x2 (FIG. 10). However, the latch member 4xe2x80x2 pivots on a vertical plane, which means that the motion of the latch member 4xe2x80x2 will be interfered by the seat 8xe2x80x2 of the bicycle, as illustrated in FIG. 10. In addition, attachment of the attaching member 2xe2x80x2 to the respective end of the top tube 1xe2x80x2 was found unreliable, and the user might be injured by the exposed pin 5xe2x80x2.
An object of the present invention is to provide a locking device for reliably locking a detachable bicycle top tube between the head top and the seat tube of a bicycle when the detachable bicycle top tube is mounted to the bicycle to be carried a car or the like.
A top tube assembly in accordance with the present invention is detachably mounted between a seat tube and a head tube of a bicycle and comprises:
a tube having two ends;
two hook-like attaching members each having a first end securely attached to an associated said end of the tube, each said attaching member further including a second end, each said attaching member being mounted around an associated one of a seat tube and a head tube of a bicycle; and
two latch members each having a first end pivotally connected to the associated end of the tube and a second end, each said latch member being pivotable along a horizontal plane between a locking position in which the second end of the latch member and the second end of an associated said attaching member are so positioned to prevent disengagement of the associated attaching member from the associated one of the seat tube and the head tube of the bicycle and an unlocking position in which the second end of the latch member is moved to a position allowing disengagement of the associated attaching member from the associated one of the seat tube and the head tube of the bicycle.
The tube may comprise two tube sections that are engaged together in a manner allowing an adjustment in an overall length of the tube. The first end of each attaching member is substantially U-shape, and the associated end of the tube comprises a non-circular engaging portion for fittingly and securely receiving the U-shape first end of the associated attaching member. The first end of each attaching member comprises a transverse hexagonal hole and a first pin hole. The associated end of the tube comprises a hexagonal hole aligned with the transverse hexagonal hole and a second pin hole aligned with the first pin hole. The first end of each latch member comprises a third pin hole aligned with the second pin hole and a slot. The slot includes an enlarged portion and an open end.
A locking means is provided for each attaching member and comprises:
a sleeve securely received in the transverse hexagonal hole of the associated said attaching member,
a stem received in the sleeve and having an end extending into the slot of the associated latch member, the stem including an enlarged locking portion that is releasably engaged in the enlarged portion of the slot of the associated latch member,
an elastic element for biasing the stem to a locking position in which the enlarged locking portion is received in the enlarged portion of the slot of the associated latch member,
a push button securely mounted to the end of the stem to move therewith;
wherein when the push button is pushed, the enlarged portion of the stem is disengaged from the enlarged portion of the slot of the associated latch member, thereby allowing pivotal movement of the associated latch member relative to the associated attaching member.
The second end of each attaching member comprises a stepped end face. The second end of the associated latch member comprises a stepped end face that is complimentary to the stepped end face of the associated attaching member. The stepped end face of the second end of the associated latch member is engaged with the stepped end face of the associated attaching member when the latch member is in the locking position.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.